It is known to determine the liquid volume of products that are filled in containers by measuring volumetric flow rate using flow meters. These known flow meters include magnetically inductive flow meters (MID's) that have no moving functional elements. Such measurements are known for their accuracy and robustness.
In the case of products containing solids or solid constituents however, measurements of the liquid volume or volumetric flow rate of filling material that is being delivered to the container are apt to be incorrect. These measurement errors can occur because, during the measurement, solids settle on the inner surfaces of the magnetically-inductive flow meters that are often used for this purpose. As a result of these solids, the product flowing through these flow meters will appear to have a highly variable conductivity. This contributes to incorrect measurements.
These inaccuracies occur even when products containing such solids or solid constituents are delivered to the container that is to be filled as separate first and second components, one of which is substantially solid-free and the other of which is a proportionally metered additional component that contains the solids or solid constituents in greater concentration, but not so great a concentration as to render it incapable of flowing.